When did the World War I ended formally?

The members of triple alliance and triple entente are:

Black hand society was formed to make the Serbian independent from Austria-Hungary which were being suppressed by them.

Archduke Franz Ferdinand was the heir of Austria. He was killed by the Bosnian student named Gavrilo Princip who was associated with black hand society.

Austria declared world war at first against Serbia.

The secret alliance made by the German chancellor with Austria- Hungary and Italy to protect Germany from France attack and isolate France is defined as triple alliance.
The treaty made by the France with Britain and Russia is defined as triple entente.

The causes of World War I are:
        - Groupism Alliance.
        - Militarism and arm force.
        - Economic Imperialism.
        - Character of Kaiser William II.
        - Balkan Crisis.
        - Desire of getting Alsace and Lorraine.

Allies and Germany were the signatories of treaty of Versailles.

If I were the representatives of Germany in Versailles treaty, I would do the following things:
        - I would request to the foreign society to minimize the problems of suppression.
        - I would accept the treaty.
        - I would not pay the money for compensation.
        - I would ask to reduce the money to be paid to the Alliance etc.

The major consequences of the first world war are:
        - Treaty of Versailles.
        - Unprecedented loss of life and property.
        - Monarchy destroyed.
        - Social changes.
        - Rise of new nations.